Effects of Reducing Indoor Air Pollution on the Adult Asthmatic Response

The investigators seek to determine the effect of placing air cleaner devices in the homes of adults with asthma on the adults' asthma health. To this end, the investigators aim to study 40 adults with asthma that are 18-50 years of age and live in Baltimore. Participants will receive either true air cleaners or sham cleaners in a blinded, randomized manner for one month, and then, after a washout period, participants will cross over and receive the other intervention (sham or true cleaner). All participants will have environmental monitoring (personal and in-home) to determine participants' particulate matter exposure, and be followed repeatedly during the 3 month study period for markers of asthma disease, including respiratory symptoms, medication and health care utilization, pulmonary function, systemic markers of inflammation, and bronchoscopic evidence of airway inflammation or epithelial cell dysfunction.

Inclusion criteria

• Age 18-50 years of age
• Non-smoker (<100 cigarettes in lifetime)
• Physician diagnosis of asthma
• Symptoms of asthma and/or reliever medication use in the past 6 months
• Living in the current residence >= 6 months within Baltimore
• Enrollment in, and completion of, the observational environmental asthma study "Inhale 1"

Exclusion criteria

• Current diagnosis of another major pulmonary disease, other significant morbidity
• Pregnancy (as defined by a positive urine pregnancy test at screening of all women of child-bearing potential)
• Planning to relocate residence or activity that necessitates travel away from home for prolonged period of time during the study period
• Current use of an air cleaner in the home